Today I twice observed Mellinus arvensis females dangling their diptera prey over the edge of oak leaves for
several minutes at a time, apparently suspended by their tongues(?), then flying with the fly slung beneath them supported by their legs to another leaf only to repeat the dangling process. Eventually they flew off with the flies, presumably to their burrows.

Can anyone tell me what this dangling business is about please? The flies seemed immobilised throughout, so I couldn't quite convince myself that they were waiting for their prey to become subdued, but that's my only theory right now.

Response from Duncan Jackson:
A reasonable guess is that they are inspecting their prey for
indications of parasitism. They don't want to provide their offspring with parasitised prey, so this is a major decision.
Its just my suggestion, but someone may know better.